How to change a preference of excel?

[nannienajera]

Version: 2008
Operating System: Mac OS X 10.5 (Leopard)

Excel is launching when my mac is starting and i dont want that, how can i eliminate that?. Because its making my mac very slow.
Thanks

 

[CyberTaz]

Right-Click the Excel Dock icon & deselect the command that's causing it